Full text unavailable from EThOS. Please contact the current institution’s library for further details.

Abstract:

Respiratory syncytial virus (RSV) is a major cause of morbidity and mortality in humans. It
repeatedly infects throughout life, suggesting induction of poor memory immune responses.
The RSV F protein is a highly conserved antigen that was studied extensively as a vaccine
both in animal models and clinical trials but has so far failed in humans. Interestingly.
evidence suggested that RSV F blocks proliferation of PHA-stimulated human PBMCs in a
contact-dependent and species-specific manner. Specifically, HRSV F preferentially inhibited
human PBLs, while bovine RSV F preferentially inhibited bovine PBLs. We aligned multiple
strains of human and bovine RSV to identify 8 species-specific residues. We hypothesized
that replacing the 8 HRSV F residues with their bovine counterparts would not alter the
antigenic or immunogenic structure of HRSV F, while removing the capacity of HRSV F to
block human PBL proliferation.
Using site-directed mutagenesis, we generated a recombinant HRSV F protein (rHRSV Fmut8)
comprising the 8 bovine residues. rHRSV Fmut8 was shown to retain reactivity when tested
with a panel of RSV F-specific MAbs, confirming that the antigenic structure was preserved.
We subsequently generated and characterised a recombinant Sendai virus efficiently
expressing our mutated HRSV F (rSeV/RSV Fmut8), found to be functional and antigenically
intact. S.eV (mwine PIVI) was chosen as a vector, as it is immunogenic but non-pathogenic
in humans, has vaccine potential against human parainfluenza virus type I (HPrv 1) and can
be easily manipulated by reverse genetics. Following intra-nasal administration to BALB/c
mice, rSeV/RSV Fmut8 induced protective immunity against RSV challenge. Human PBMC
proliferation block experiments revealed that HRSV efficiently blocks inhibition, in which
RSV F plays a role. If confirmed, abrogation of the human PBL proliferation block combined
with its protective efficacy in vivo, suggests that rSeV/RSV Fmut8 will constitute a very
interesting and novel RSV vaccine candidate.